Is Running Enough For Your Bones' Health?

Sports doc says some runners' bones as bad as those in inactive people.

Most runners know that running builds bone health. What's known as Wolfe's Law states that, in healthy people, bones respond to stress by reforming to better handle that stress. For runners, that means the weight-bearing bones of the legs, pelvis and spine tend to be stronger than the same bones in inactive people.

But as Kirk Scofield, M.D., points out in a research review in Current Sports Medicine Reports, some runners' bone density is no better than that of their sedentary peers. Low bone density can lead to stress fractures now and frailty later. In addition, notes Scofield, the relatively low-impact, high-frequency stress that running supplies to bones isn't as effective in buidling density as are higher-impact, less-frequent, multi-directional stresses such as those bones encounter during activities like court sports.

"Some runners do have poor bone health, particularly runners that are not taking in enough calories, either because they restrict their calorie intake, or because they are burning so many calories they just have difficulty keeping up," Scofield, a marathoner, Nordic skier and triathlete, told Runner's World Newswire. "This includes many women of child-bearing age who have stopped having regular menstrual periods due to their running."

That latter condition can often be triggered by not consuming enough calories to meet the body's energy needs, which extend beyond simply having enough fuel to get through runs. What Scofield calls "energy availability" is, he writes in his research review, "the pool of energy that is available to fuel a wide array of normal physiological functions. Reproductive function, growth, and maturation, including bone formation, are among some of the physiologic functions supported by [energy availability]."

That running's bone-health benefits apply primarily to weight-bearing bones is good, Scofield says, because those are the bones "most susceptible to disabling fractures later in life." At the same time, it's worth remembering that full-body bone health is important. "Additional steps to strengthen bones in the arms would include weight training and running with small weights or water bottles carried in the hands," Scofield says. "The spine can additionally be strengthened by occasionally carrying a back pack with water or a small amount of weight on hikes or long trail runs."

Scofield has become convinced by his look into bone health to alter his approach to exercise.

"I have been incorporating more cross-training into my routine lately and qualified for Boston last spring with a PR [of 3:20], while incorporating only 3 quality runs per week after reading Runners World'sRun Less Run Faster [book]," he says. "I think I feel stronger with all the cross-training and am hoping to have a healthier, more well-rounded body from it long-term."